Trouble finding a fix to an exploit with a craftable "lesser" elytra

I was making a datapack for my SMP and while doing so I decided to add a recipe for an elytra that is weaker than a normal elytra in a sense. I just made it craft an elytra with curse of vanishing and a high repair cost so it can't be repaired or enchanted with other enchants. However it was pointed out to me that people could use these weak elytras in the crafting grid to make a regular elytra, they could grindstone a weak elytra and enable upgrading and repairing it. I went in knowing how to solve the anvil but I made this oversight and I have absolutely no clue on how to fix this.